Change in Birth Rate Before and After Bariatric Surgery in France

Bariatric surgery worldwide has grown significantly over the past years and is performed, in a vast majority, in women of childbearing age. The impact of these procedures on birth rates remains largely unknown.

The main objective was to study the evolution of the birth rates in these women, before and after bariatric surgery and in comparison with women from the general population. The secondary objectives were to compare the birth rates before and after surgery according to the Body Mass Index (BMI) (BMI 40–50 versus >50 kg/m²).

Our analyses are based on a national medico-administrative database. All women of childbearing age and who had bariatric surgery between 2012 and 2016 were included, and we included all deliveries between 2012 and 2018 in this population. We compared the birth rates before and after bariatric surgery. National statistics (INSEE, Institut National de la Statistique et des Etudes Economiques) were used for comparison with women from the general population.

A total of 69,932 women were included between 2012 and 2016, with a median age at surgery of 33 years [27; 39]. Among them, 9391 (13%) had a BMI over 50 kg/m² before surgery, 46,818 (67%) benefited from a sleeve gastrectomy (SG), and 23,376 (33%) from a gastric bypass (GBP). Birth rates tend to be smaller after surgery compared to before surgery for women under 27 years (OR: 0.92, CI95% [0.88; 0.96]), while being not different after 27 in both groups (OR: 1.00, CI95% [0.97; 1.03]). Birth rates of obese women who have benefited or will benefit from the bariatric surgery were higher than the general population, with a peak at a younger age, and then decline earlier than the general population. Trends were different according to BMI class. Birth rates were higher for women with BMI between 40 and 50 kg/m² compared to women with BMI greater than 50 kg/m² (OR=1.28, CI95% [1.21; 1.36]) before surgery while slightly lower after surgery (OR=0.95, CI95% [0.91; 0.99]).

We showed that birth rates after bariatric surgery were not different before and after bariatric surgery except for women under 27 years old who had a smaller birth rate. Interestingly, we observed an improvement of birth rates after surgery for women with a BMI of 50 kg/m² or more.